Chables francis jenkins



Dec. 13, 1921. I e, 16,818

a C. F. JENKINS PNBUMATICALLY CONTROLLED LIGHT VALVE Original Filed Auz. so, 1922 [mamas Fmus JENKms.

Reissued Dec. 13, 1927.

UNITED STATES PATENT OFFICE.

CHARLES FR ANCIS JENKINS, OF WASHINGTON, DISTRICT 0]? COLUMBIA, ASSIGNOR TO JENKINS LABORATORIES, A CORPORATION.

PNEUMATICALLY-CONTROLLED LIGHT VALVE.

Original No. 1,525,548, dated February 10, 1925, Serial No. 585,816, filed August 30, 1922. Application for reissue filed January 10,

trated in the accompanying drawings Figure 1 and Figure 2 (the latter a detail view) in which A is a cup-shaped magnet, with-a wire coil,B encircling a central member extending upward from the bottom thereof. C is an elastic iron diaphragm; D a stiff iron disc adjacent to the diaphragm, both the disc and the diaphragm being fixed to the rim of the cup-like magnet. The disc D has an opening therein in which is supported a thin iron valve member slightly smaller than the opening. This valve is held by magnetic attraction, with the "edge against the edge of the opening in the disc D, and in the same general plane by the same force. valve a small reflecting spot E has been polished or a small mirror mounted. from which light coming from a source F is reflected to the mask M. The shadow of H (an opaque body) is made to fall upon the aperture N by adjustment of the various parts when at rest, consequently no light can pass through the aperture to the photographic plate S.

en, however, fluctuating current from some outside source flows through the coil B the diaphragm is vibrated, with the result low the movement of the diaphragm, lying as it does between the constant density of the air outside and the changing density of the air imprisoned between the diaphragm and disc.

Obviously the movement of the valve imparts a corresponding movement to the light (and shadow) from the mirror surface as it oscillates in greater or lesser amplitude,

and consequently more or less light passes through the aperture N as the shadow of H moves more or less from over the aperture. And as the volume of light admitted through the aperture N corresponds to the amplitude of the valve vibration, and the latter results Upon the i 1927! Serial No. 160,317.

directly from the varying strength of the current in the coil B, it follows that the light value passing through N corresponds directly to the current strength in coil B. Consequently the photographic plate exposure value at any particular movement is practically proportional to the current strength.

The operation of the valve by means of the air imprisoned thereunder is not only convenient and simple, but provides a certain elasticity of connection which it has been found adds materially to the certainty and smoothness of action of the light beam, while at the same time the magnetic grip of the valve disc edge prevents the chattering which often results from a pin hinge action where high speeds are involved.

It is obvious that with the shadow of the opaque body lying over the opening in the mask M, and the mask illuminated on either side of the opening, that the movement of the shadow in either direction across the opening permitslight to pass through the opening. If the shadow moves far enough ,to wholly uncover the opening the light falling on the plate S will be of maximum strength, while if it moves alesser distance a lesser amount of light passes the opening valve to permit air'to pass it in combination I by said valve for controlling the effective 8. In apparatus of the class described, a

value of a beamof light from said source, said means including a light reflecting surface carried by the valve in the movements thereof.

3. In apparatus of the class described, the combination of a vibrating mirror, a light source, means for directing the light from the source onto said mirror, an opaque member smaller than the field of the lightsource, and located between the light source and the mirror, a receiving surface upon which the light is reflected from the mirror, and an apertured mask between the receiving surface and the mirror.

'4. In apparatus of the class described, the combination of a vibrating mirror, a light source, means for directing the light from the source onto said mirror, an opaque memher smaller than the field of the light source, andlocated between the light source and the mirror,.a receiving surface upon which the light is reflected from the mirror, an apertured mask between the receiving surface and the mirror, and means for vibrating;

the mirror.

5. In apparatus of the class described, the combination of a vibrating mirror, a light source, means for directing the light from the source onto said mirror, an opaque member smaller than the field of the light source, and located between the light source and the mirror, a receiving surface u on which the light is reflected from the mirror, an apertured mask between the receiving surface and the mirror, and pneumatic means for vibrating the mirror.

6. In apparatus of the class described, the combination of a vibrating mirror, a light source, m'eans for directing the'light from the source onto said mirror, an opaque member smaller than the field of the light source, and located between the light source and the mirror, a receiving surface upon which the light is reflected from the mirror, an apertured mask between the receiving surface and the mirror, and magnetic actuated pneumatic means for vibrating the mirror.

7.. In apparatus of the class described, the a combination of a vibrating mirror, a light source, means for directing the light from the source onto said mirror, an opaque member smaller than the field of the light source, and located between the light source and the mirror, a receiving surface upon which the light is reflected from the mirror, an apertured mask between the receiving surface and the mirror, and a mirror supported in place by magneticmeans.

apertured mask between the movlng member and the photographic plate, and an opaque member interposed in the light beam in such position as to cast a shadow upon the aperture in said mask.

10. In apparatus of the class described, the

combination of a source of light of constant intensity, means for forming a tubular beam of light having a dark area from said source and directing it towards a light-receiving surface, a light-intercepting screen having an aperture substantially the same size as the dark' area within said beam, said screen being interposed between said source and said surface in a position to normally cut off all the light, and means for shifting said beam with respect to said screen to permit varying amounts of light to pass to said surface through said aperture.

11. In apparatus of the class described, the

combination of a source of light of constant 'intensity, means for forming a beam of light having a dark section and directing it towards a light-receiving surface, a light- .interceptin screen having an aperture substantially t e same size as the dark area of said beam, said screen being interposed between said source and said surface in a position to normally out off all the light, and means for shifting said beam with respect to said screen to permit varying amounts of light to pass to said, surface through said aperture.

'12. In an apparatus of the class described, a source of light and a pneumatically actuated leaky valve magnetically supported to form a connect-ing hinge, in combination with means operated by the valves for con,- trolling the effective value of a beam of light from said source.

In testimony whereofI aflix my signa ture. 

